1. Field of the Invention
The present invention relates to a method for fabricating a semiconductor-mounting body comprising a semiconductor device mounted on a substrate and an apparatus for fabricating a semiconductor-mounting body.
2. Related Art of the Invention
As the fining art of a semiconductor process advances, the form of a semiconductor package is also developed from QFP to xcexc BGA and CSP (chip size package), and moreover flip-chip mounting of directly connecting a semiconductor bare chip onto a substrate.
Above all, in the case of the flip-chip mounting, because a semiconductor device and a substrate are directly mounted, application development to units requiring a high-speed processing may be further accelerated. To realize the above mounting art, a mounting-process art is indispensable and a fabrication equipment and a process art for joining a semiconductor device with a substrate so that the reliability can be secured in a short time are particularly important.
A case of performing mounting by using the flip-chip mounting art is described below by referring to the accompanying drawings. FIG. 10 is an illustration for explaining the configuration of a structure in which a semiconductor device is flip-chip-mounted on a substrate by using a conventional apparatus for fabricating a semiconductor-mounting body and its fabrication procedure and FIG. 11 is a schematic view for performing flip-chip mounting by setting an elastic body to a position where a heat source contacts a semiconductor device. In FIGS. 10 and 11, the same portions are provided with the same symbol.
As shown in FIG. 10, a bump 16 having a two-stage protrusion shape is formed on an electrode pad 15 of a semiconductor device 2 by melting an Au wire and then, a conductive adhesive 17 is transferred to the two-stage protruded portion of the bump 16. Then, the semiconductor device 2 is faced down and joined with a terminal electrode 18 pattern-formed on a substrate 1 to cure the conductive adhesive 17.
Then, a liquid epoxy-based sealing resin 11 is injected into the gap between the semiconductor device 2 and the substrate 1 and then, as shown in FIG. 11, an elastic body 22 is set to the position with which a heat source 7 and semiconductor device 2 contact to cure the sealing resin 11 while pressing the back of the semiconductor device 2 by the elastic body 22.
A base table 21 is a table to which the substrate 1 is set. Thus, by curing the sealing resin 11 while pressing the semiconductor device 2 at a load larger than the pushing-up force of the semiconductor device 2 due to the thermal expansion when the searing resin 11 is heated, it is possible to minimize increase of a connection resistance or imperfect joining states.
However, there may be no problem about the case in which the substrate 1 is thick and has a thermal expansion coefficient close to that of the semiconductor device 2 and a small number of semiconductor devices 2 are flip-chip-mounted like the case of the conventional configuration shown in FIG. 10. As shown in FIG. 11, however, when flip-chip-mounting the semiconductor devices 2 different from each other in thickness and shape on the substrate 1, stresses are concentrated on the highest semiconductor device 2 and the highest semiconductor device 2 is greatly damaged, because pressure is inevitably applied from the thickest semiconductor device 2 to lower ones in order.
Even if using a method for absorbing fluctuations in heights of the semiconductor devices 2 by cushions such as elastic bodies 22A, 22B, and 22C at the position where the heat source 7 contacts the semiconductor devices 2, it is difficult to apply a uniform pressure to the elastic bodies 22A and 22C other than the elastic body 22B because stresses are further concentrated on the elastic body 22B as the thickness fluctuation of the semiconductor devices 2 increases.
Moreover, a position shift may occur in the semiconductor devices 2 due to the elastic deformation of the elastic body 22B.
Furthermore, when many semiconductor devices 2 having different thicknesses and shapes are present on the substrate 1, it is necessary to set the above elastic bodies to positions corresponding to all the semiconductor devices 2. Therefore, a fabrication system is inevitably restricted to a dedicated system for only one type of product. Therefore, in the case of many types of products, it is necessary to use an elastic body for each type of produce each time and thus, there is a problem in versatility.
Therefore, it is difficult to flip-chip-mount many semiconductor devices having different thicknesses and shapes by the conventional fabrication method.
The present invention is made to solve the above conventional problems and its object is to provide a method for fabricating a semiconductor-mounting body and an apparatus for fabricating a semiconductor-mounting body capable of fabricating a semiconductor-mounting body by substantially uniformly pressurizing a plurality of semiconductor devices having different thicknesses and shapes when mounted on a substrate.
One aspect of the present invention is a method for fabricating a semiconductor-mounting body having at least one semiconductor device mounted on a substrate and a sealing resin set in the gap between the substrate and the semiconductor device, comprising:
a first step of setting a flexibly deformable sheet on a face of the semiconductor device not facing the substrate; and
a second step of generating an air-pressure difference between the side where the semiconductor device is not present and the side where the semiconductor device is present on the basis of the sheet so that the air pressure at the side where the semiconductor device is not present becomes higher than the side where the semiconductor device is present and pressurizing the semiconductor device by the sheet after the first step.
Another aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein at least a part of the sheet does not contact the substrate in the second step.
Still another aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein the second step is executed by supplying predetermined gas to the side of the sheet where the semiconductor device is not present and excluding gas from the side where the semiconductor device is present.
Yet still another aspect of the present invention is the method for fabricating a semiconductor-mounting, wherein the sheet does not contact the semiconductor device and/or the sealing resin at least immediately before the pressurization is performed.
Still yet another aspect of the present invention is the method for fabricating a semiconductor-mounting, further comprising a third step of fixing the circumference of the sheet set on the semiconductor device at least immediately before pressurizing the sheet.
A further aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein looseness is removed from the sheet before pressurizing the sheet.
A still further aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein looseness is removed from the sheet by fixing the circumference of the sheet from the outside to the inside of the sheet in order.
A yet further aspect of the present invention is the method for fabricating a semiconductor-mounting body, further comprising a fourth step of heating the sheet by a heater from the side where the semiconductor device is not present when pressurizing the sheet.
A still yet further aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein the distance between the set sheet and the heater is adjusted.
An additional aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein the sheet is a rubber sheet formed by silicon or Buna-S and having a thickness of 0.01 to 3 mm.
A still additional aspect of the present invention is the method for fabricating a semiconductor-mounting s, wherein the sheet is a resin sheet formed by any one of polyimide, fluoro resin, polyphenylene sulfide, polypropylene, polyether, polycarbonate, and chrolosulfonated polyethylene, or a compound of them and having a thickness of 0.01 to 1 mm.
A yet additional aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein the sheet is a metallic sheet formed by aluminum, copper, or stainless steel and having a thickness of 0.01 to 0.5 mm.
A still yet additional aspect of the present invention is the method for fabricating a semiconductor-mounting, wherein a mold-releasing treatment is applied to the face of the sheet contacting the semiconductor device.
A supplementary aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein a coloring treatment for improving heat absorption is applied to the face of the sheet not contacting the semiconductor device.
A still supplementary aspect of the present invention is the method for fabricating a semiconductor-mounting, wherein a colored additive for improving heat absorption is contained in the sheet.
A yet supplementary aspect of the present invention is the method for fabricating a semiconductor-mounting body, further comprising a fifth step of setting a support frame for supporting the sheet nearby the semiconductor device before setting the sheet.
A still yet supplementary aspect of the present invention is an apparatus for fabricating a semiconductor-mounting body having at least one~ semiconductor device mounted on a substrate and a sealing resin set in the gap between the substrate and the semiconductor device, comprising:
setting means of setting a flexibly deformable sheet on a face of the semiconductor device not facing the substrate; and
pressurizing means of generating an air-pressure difference between the side where the semiconductor device is not present and the side where the semiconductor device is present so that the air pressure at the side where the semiconductor device is not present becomes higher than the side where the semiconductor device is present on the basis of the sheet and pressurizing the semiconductor device by the sheet.
One aspect of the present invention is the apparatus for fabricating a semiconductor-mounting body, wherein at least a part of the sheet does not contact the substrate when the pressurization is performed.
Another aspect of the present invention is the apparatus for fabricating a semiconductor-mounting body, wherein the pressurizing means supplies predetermined gas to the face of the sheet where the semiconductor device is not present and excludes gas from the side where the semiconductor device is present.
Still another aspect of the present invention is the apparatus for fabricating a semiconductor-mounting body, wherein the sheet does not contact the semiconductor device and/or the sealing resin at least immediately before the pressurization is performed.
Yet still another aspect of the present invention is the apparatus for fabricating a semiconductor-mounting body, further comprising fixing means of fixing the circumference of the sheet set to the semiconductor device at least immediately before the sheet is pressurized.
Still yet another aspect of the present invention is the apparatus for fabricating a semiconductor-mounting, further comprising looseness removing means of removing looseness from the sheet before pressurizing the sheet.
A further aspect of the present invention is the apparatus for fabricating a semiconductor-mounting body, wherein looseness is removed from the sheet by fixing the circumference of the sheet from the outside to the inside of the sheet in order.
A still further aspect of the present invention is the apparatus for fabricating a semiconductor-mounting, further comprising heating means of heating the sheet from the side where the semiconductor device is not present when the sheet is pressurized.
A yet further aspect of the present invention is the apparatus for fabricating a semiconductor-mounting, further comprising distance adjusting means of adjusting the distance between the set sheet and the heating means.
A still yet further aspect of the present invention is the apparatus for fabricating a semiconductor-mounting body according to 17 th or 18 th inventions, wherein the sheet is a rubber sheet formed by silicon or Buna-S and having a thickness of 0.01 to 3 mm.
An additional aspect of the present invention is the apparatus for fabricating a semiconductor-mounting body, wherein the sheet is a resin sheet formed by any one of polyimide, fluoro resin, polyphenylene sulfide, polypropylene, polyether. polycarbonate, and chrolosulfonated polyethylene, or a compound of them and having a thickness of 0.01 to 1 mm.
A still additional aspect of the present invention is the apparatus for fabricating a semiconductor-mounting, wherein the sheet is a metallic sheet formed by aluminum, copper, or stainless steel and having a thickness of 0.01 to 0.5 mm.
A yet additional aspect of the present invention is the apparatus for fabricating a semiconductor-mounting, wherein a mold-releasing treatment is applied to the face of the sheet contacting the semiconductor device.
A still yet additional aspect of the present invention is the apparatus for fabricating a semiconductor-mounting, wherein a coloring treatment for improving heat absorption is applied to the face of the sheet not contacting the semiconductor device.
A supplementary aspect of the present invention is the apparatus for fabricating a semiconductor-mounting, wherein a colored additive for improving heat absorption is contained in the sheet.
A still supplementary aspect of the present invention is an apparatus for fabricating a semiconductor-mounting body, further comprising a support frame to be set to support the sheet nearby the semiconductor device before the sheet is set. conductor device, comprising: